The influences of different conversions on structure and properties of high trans-1,4-butadiene(Bd)-co-isoprene(Ip) rubber (TBIR) synthesized with supported TiCl4/MgCl2catalyst and hydrogen regulation was studied. The TBIR could be used in production of high performance rubber. Results showed that there were butadiene units with long sequence lengths in the TBIR in the initial period of polymerization and sequence lengths of isoprene units grew with increase of the conversion. The mechanical properties such as green strength, elongation at break, permanent set, abrasion loss and rebound increased with increase of the conversion. DMA analysis showed that anti-wet property of TBIR vulcanizate descended and its heat build-up increased with increase of the conversion. It was discovered that the most suitable range of conversions was 55%-65% when initial feed ratio of n(Bd): n(Ip) was 0.25.
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The determination method for 14 kinds of metal elements in pipeline transportation crude oil was established using crucible and ICP-AES. The test results show that quartz crucible is a good choice for ashing crude oil and the suitable ashing conditions for pipeline transportation crude oil are 550 °C, 3 h. And a variety of elements can be detected accurately at the same time with sampling once. The element detection limit of the method is between 0.000 6-0.723 0 mg/L, RSD<7. 0% (except cadmium 28. 75%), and the standard recovery rate of 91%-115%.
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A method for the simultaneous determination of 7 arsenic species was developed with high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was extracted with artificial gastric juice. The HPLC separation was performed on an anion analytical column utilizing a gradient elution program of ammonium carbonate and water as the mobile phase. Identification and quantification were achieved by ICP-MS. Good linearities of 7 arsenic species wem observed in the range from 1μg/kg to 50μg/kg with the correlation coefficients greater than P0.999. The average recoveries of 7 arsenic species spiked at the three levels of 1, 2 and 10μg/kg ranged from 84. 3% to 106. 6% with the relative standard deviations of 1. 4% -4. 2%. The quantification limits of 7 arsenic species were 1μg/kg. The method was, proved to be good reproducibility, high sensitivity and simple preprocessing. This method i^ suitable for the simultaneous determination of 7 arsenic species in chicken muscle and chicken liver.
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